Tuberculosis among young contacts of patients with multidrug-resistant pulmonary tuberculosis in a reference hospital

Objectives Young contacts of pulmonary tuberculosis (TB) patients face a higher risk of TB. Still, few studies have evaluated this risk among contacts of patients with pulmonary multidrug-resistant tuberculosis (MDR-TB). This study aimed to describe the incidence rate and the prevalence of TB infection (TBI) and TB disease (TBD) in young contacts of patients with MDR-TB. Methods The authors retrospectively evaluated contacts of patients with pulmonary TB aged 0 to 19 for TBI and TBD in Rio de Janeiro between 2006 and 2016. Based on the drug susceptibility pattern and/or therapeutic regimen of the index case, contacts were classified into MDR-TB and non-MDR-TB contacts. A tuberculin skin test ≥ 5 mm was considered positive. Preventive therapy with isoniazid was offered to eligible contacts. Bivariate and multivariate logistic regressions estimated factors associated with TBI. Results 439 contacts were screened; 129 were MDR-TB and 310 were non-MDR-TB contacts. TBI prevalence was 68.2 % in MDR-TB vs. 61.9 % in non-MDR-TB contacts (p = 0.23). Tuberculin conversion was higher among MDR-TB contacts (45.5 % vs. 17.1 %; p = 0.04). TBD incidence rate was 47.7 in non-MDR-TB and 179.6 per 100,000 person-months in MDR-TB contacts (p = 0.65), for a total TBD prevalence of 2.5 %. The overall TPT completion rate was 67.2 %; 71.5 % in non-MDR-TB and 59 % in MDR-TB contacts (p = 0.04). Conclusion The authors identified a high prevalence of TBI among contacts of pulmonary MDR-TB and non-MDR-TB patients, with a higher tuberculin conversion rate in MDR-TB contacts, highlighting the urgency of effective TPT regimens for young contacts of patients with pulmonary MDR-TB.